Dental appliance.



S. PRESTON. DENTAL APPLIANCE. APPLICATION FILED oc. 31, 191s.y

STEPHEN PRESTON, OF ROANOKE, VIRGINIA.

DENTAL APPLIANGE.

Specification of Letters Patent.

Patented Aug. 14, 1917.

Application filed October 31, 1916. Serial No. 128,793.

To all whom t may concern:

Be it known that I, STEPHEN PRESTON, acitizen of the United States, residing at Roanoke, in the county of Roanoke and State of Virginia, have invented certain new and useful Improvements in Dental Appliances, of which the following is a specification.

vThis invention relates to a device for use in making cast metal dental inlays such as described in U. S. Patent No. 983,597, issued to W. H. Taggart, on Feb. 7 1911. The apparatus is intended for use with the vacuum casting of these inlays and provides a simple and convenient and safe means for applying the vacuum pressure to the investment material in the Crucible.

With such objects and others in view the invention consists of the formation, combination and arrangement of parts as will be herein'described and claimed.

In the accompanying drawings, Figure 1 is a planview of the device of my invention and Fig. 2 la front elevational view of the same, the vacuum age being shown in slightly different positions in these two figures.

Referring to these drawings, the device is intended to be secured to a work bench 1 and comprises a standard or T-shaped litting 2 having a vertical hollow stem 3 with two hollow lateral branches 4 and 5 extending horizontally in opposite directions from the same near its upper extremity. At the point of intersection of the vertical and-horizontal cavities of these parts is a stop cock 6 having a handle 7.V This cock controls communication between the cavity of the vertical stem 3 and those of the horizontal branches 4 and 5 in such manner that in one position (that shown in the drawings) the cock 6 allows fluid communication between the cavity of the vertical stem and those of both Vof the branches. When the cock is given a quarter turn in clockwise direction communication remains between the cavity of the vertical stem and that of the branch 4 and shuts oil" communication with the cavity of the branch 5. y

Extending horizontally outwardly from the branch 4 is a communicating tube 8 which terminates in the hollow L-shaped fitting 9, this fitting being screw-threaded on the tube 8 so as to allow it to be swung thereabout into different positions. Attached to the other outlet of the fitting 9 is a vacuum gage 10.' It is desirable that this gage be arranged to swing to different angles of vision as indicated in the two gures of the drawings, hence the screw .threaded connection between 8 and 9.

Extending horizontally outwardly from the branch 5 is a communicating tube 11 which terminates in a similar hollow L- shaped fitting 12. Extending vertically upward from and attached to this L-iitting by means of a screw thread is a communicating pipe 13, the same terminating in a horizontal Crucible plate 14, the same being pierced at 15 to register with the cavity of the tube 13.

The customary crucible with the investment therein is placed on this Crucible plate and gold or other metal is melted by means of a blow pipe or the like. By exhausting the air from beneath the crucible a pressure is exerted upon the molten metal to force it into the mold. This process is well known in the dental art and as it forms no part of the present invention it will not be gone into at length herein.

From the bottom of the stem 3 a tube. 16 extends downward through a suitable hole in the work bench 1. To this tube is attached a hose 17 which leads from any suitable air exhauster which is preferably located at a distance from the present mechanism. Thus the air may be exhausted from the cavities of my device.

At all times it is desirable to know the amount of vacuum created by the exhauster and existing in the device and at times it is necessary to shut off the vacuum from beneath the crucible. ment of parts forms a convenient and compact arrangement whereby these ends may be attained. The cavities of the several parts of the present device are made as small as practical so as to aggregate only a very small reservoir capacity. By now locating the air exhauster at a remote distance it will be seen that the registration of the gage 10 will represent the vacuum existing in all of the local parts. In mechanisms where considerable reservoir capacity is supplied near the crucible plate andl gage itV frequently happens that the registration of the gage will not represent the vacuum lexisting' under the investment` and for investments of different densities a correction must always be made to allow forv the varying leakages through these investments.

It sometimes happens that the investment The present arrangeper will br'eak away and the molten gold will follow down the tubes to the stop cock. To arrest the passage of such metal 1 provide a strainer at the base of the tube 13 which is made as follows: The fitting 12 is provided with an annular shoulder 18 upon which rests pierced metal plate or disk 19. Upon this disk is placed a layer 20 of noninflammable and highly refractory material such as asbestos fiber. r1`his strainer while permitting the passage of air, will yet arrest the flow of the molten metal. By unscrewing the tube 13 from the 1...-fitting 12 the gold may be recovered and the strainer renewed or cleaned. v

In order to support the entire device a collar or base 21 is attached to the standard 2, this base being provided with screw holes 22 for securing the outfit to the work bench. This collar surrounds the lower end of the stem 3 immediately beneath a bead 23 against which the metal of the collar is expanded.

The device thus described is compact, neat and convenient and locates all the parts in positions best suited for their respective use.

Having thus described my invention, what 1 claim is:

1. In a device of the class described a standard having a hollow vertical stem and two hollow branches therefrom near its upextremity, a stop cock in the same controlling` communication between the cavity of the vertical stem and those of the branches, the said cock being so arranged that in one position both of said branch cavities are in open communication with the cavity of the stem and in another position the cavity of the first ofv said branches is in communication with the cavity of the stem and the cavity of' the second of said branches shut off therefrom, a tube extending outwardly from the first of said branches and having a vacuum gage attached thereto,

'a tube extending outwardly from the second of said branches and having a horizontal crucible plate. attached thereto, there being a hole in said ciucible plate in communication with the cavity of the attached tube,

all of said cavities being of such size as to form in the aggregate only a small reservoir capacity, and in combination therewith, means remote from the device for producing a vacuum in the vertical stem of the said standard. l

the cavity of the first of said branches is in communication with the cavity of the stem and the cavity of the second of said branches shut off therefrom, a tube extending outwardly from the first of said branches and having a vacuum gage attached thereto, a tube extending outwardly and upwardly from the second of said branches and having a horizontal crucible plate attached thereto, there being a hole in said crucible plate in communication with the cavity of the attached tube, a collar surrounding said vertical stem and aiiixed thereto, said collar forming a supporting base for the entire device and having means for securing the same to a work bench, and in combination therewith, means for producing a vacuum in the vertical stem of the said standard.

3. 1n a device of the class described a standard having a hollow vertical stem and two hollow branches therefrom near its upper extremity, a stop cock in the same controlling communication between the cavity of the vertical stem andv those of the branches, the said cock being so arranged that in one position both of said branch cavities are in open communication with the cavity of the stem and in another position the cavity of the first of said branches is in communication with the cavity of the stem and the cavity of the second of said branches shut off therefrom, a tube extending outwardly from the first of said branches and having a vacuum gage attachedthereto, a tube extending outwardly from the second of said branches and having a horizontal crucible plate attached thereto, there being a hole in said crucible plate in communication with the cavity of the attached tube, a strainer of non-inflammable and highly refractory material introduced in said tube between the said crucible plate and the stop cock, and in combination therewith, means for producing a vacuum in the vertical stem of the said standard. w

4. 1n a device of the class' described a standard comprising a T-shaped fitting havlateral brcnches extending horizontally in opposite directions therefrom near its upper extremity, a stop cock in the same located at the intersecting point of the vertical and ing a hollow vertical stem and two hollow,

horizontal cavities and controlling communication between the cavity of the vertical stem and those of the branches, the said cock being so arranged that in one position both of said branch cavities are in open communication with the cavity of the stem and in another position the cavity of the rst of said branches is in communication with the cavity of the stem and the cavity of the second of said branches shut olf therefrom, a tube extending horizontally out-- wardly from the first of-said branches and terminating in an tfshaped fitting,

the same being attached to the end of said tube by means of a screw-threaded joint, said T- shaped standard having a vacuum gage attached thereto at its other outlet, a tube extending horizontally outwardly from the second of said branches and terminating in a similar L-shaped fitting, a tube extending vertically from the other outlet of said T- shaped standard and having a horizontal crucible plate attached thereto at its upper extremity, there being a hole in said crucible plate in communication with the cavity of the attached tube, and in combination therewith, means for producing a vacuum in the vertical stem of the said standard.

5. In a device of the class described, a

crucible plate, a tube extending downwardlyA therefrom, a stop cock in said tube, a strainer of non-inflammable and highly refractory material interposed between the said crucible plate and the stop cock, said strainer embodying a pierced metal plate, a supporting stop therefor internal of said tube, and a layer of non-inflammable and highly refractory straining material on said plate, said straining material being susceptible of the passage of air therethrough.

In testimony whereof, I aifiX my signature i in presence of two witnesses.

STEPHEN PRESTON.

Vitnesses:

CLARE C. PETERS, KYLE T. LEE.

Copies of this patent may be obtained for ve cents each, by addressing the "Commissioner of Patents. Washington, D. C. 

